In the goldfish, a severed optic nerve will regenerate within a few months of being cut, reforming the original pattern of connections between the eye and the brain and restoring visually guided behaviors. The present study is aimed at identifying specific proteins which are involved in such aspects of this process as neurite outgrowth, contact guidance, intercellular recognition and synaptogenesis. Double labeling and electrophoretic separation will be used to contrast the protein synthesis patterns of a regenerating and the contralateral intact eyes from individual goldfish. The studies will examine proteins in various phases of axoplasmic transport, using the axon as a column to separate different functional groups of proteins from each other according to their transport velocities. The first studies will focus on the rapidly transported proteins, since it is this phase which contains vesiculated membranous material that becomes incorporated in the growing tips and, later on, the axon terminals. Our preliminary studies have already identified several proteins transported in this phase whose labeling is greatly increased (greater than 40%) during regeneration (85 and 110,000 daltons), and others whose labeling is greatly decreased (20-37,000) from day 29 of regeneration to day 62. Two-dimensional electrophoretic methods will be used to better separate and characterize these proteins and, using preparative methods, to purify them. Eventually, we will raise antibodies against the species of interest to use for immunochemical mapping and for examining the physiological effects of manipulating the proteins. Isotope incorporation methods will be further used to determine which particular carbohydrate groups characterize the proteins and to contrast proteins differentially transported to different topographic regions of the tectum (i.e., chemo-affinity markers). An in vivo procedure will also be developed for studying the binding characteristics of retinally synthesized proteins to cells of the optic tectum.